body, ul, ol, li, p, h1, h2, h3, h4, h5, h6,
form, fieldset, img, div, pre {
    margin: 0;
    padding: 0;
    outline: 0;
    border: 0;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    user-select: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    cursor: default;
}

ul, li, ol {
    list-style-type: none;
}

select, textarea {
    background: transparent;
    border: none;
}

button:focus, input:focus, code:focus, pre:focus {
    outline:none;
}

:root {
    background-color: #373739;
}

.calculator {
    width: 100%;
    height: 250px;
}

.calculator-terminal {
    width: 190px;
    height: 50px;
    overflow: hidden;
    line-height: 50px;
    color: #ffffff;
    font-size: 24px;
    text-align: right;
    padding: 0 5px 0 14px;
    background-color: #373739;
    border: 1px solid #373739;
    box-sizing: border-box;
}

.calculator-control {
    width: 200px;
    height: 200px;
}

.calculator-control-button {
    float: left;
    width: 50px;
    height: 40px;
    line-height: 40px;
    color: #e8e8e8;
    background-color: #686869;
    text-align: center;
    font-size: 15px;
    border-right: 1px solid #373739;
    border-bottom: 1px solid #373739;
    box-sizing: border-box;
    cursor: default;
}

.calculator-control-button:active {
    background-color: #a8a7a8;
}

.dark {
    color: #e3e4e4;
    background-color: #4a4a4b;
}

.orange {
    color: #fff0df;
    background-color: #fd9e2b;
}

.border-first {
    border-left: 1px solid #373739;
}

.button-wider {
    width: 100px;
}